PHP Debugger

For those PHP developers out there... i need help here...

I am looking for a good PHP IDE for debugging. I wanted to debug PHP scripts like doing VB6, youu know where one can finger with F8 and the highlighted lines.

From google, I realized that there are a few of them...

1. Zend PHP Studio
2. Nusphere - debug demo
3. Xored Software - debug features

Marcomedia Dreamweaver can't do the job because it doesn't provide built-in PHP engines. This can be witnessed from... One have to test the scripts outside of the IDE using external PHP engine + Web server.

This is very obvious as such that Dreamweaver doesn't provide the luxury of "play" button.

Any open source ?

However, Dreamweaver provides support for chinese font editing while Nusphere don't.

Anyone has free software ?